Azonitriles containing tertiary amino substituents



Patented July 29, 1952 "AZONITRILES CONTAINING TERTIARY,

v AMINO SUBSTITUENTS John Raven Johnson, Ithaca, N. Y., assignor to E. I. du Pont de Ncmours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application May 26, 1949, Serial No. 95,572

6 Claims. ('01. 260-152) new compounds. A further object is the provisionof new catalysts or initiators for addition polymerization of polymerizable ethylenic compounds. Another object is the provision'of new catalysts or initiators for chain mechanism reactions promuted by free radicals. Other objects will appear hereinafter. 7

These objects are'acc'omplished by the inventionof azo-"compounds having an acyclic azo, I-I: N;- group which has at least one but preferably each of its valences satisfied by, i. e.,

bonded to a non-aromatic radical, the azo group being bonded to tertiary carbon of said radical, i. e., to a. carbon attached to three other carbons, one of-which has-all of its remaining valences satisfied by' oxygen and/or nitrogen, i. 6., has all its remaining valences satisfied only by elements of atomic number of seven to eight and said radical aliphatic in character having a carbon bearing a tertiary amino group; The invention also includes the use of these azo c mp in-the addition polymerization of'ethylenic compounds subject to addition polymerization; By virtue of the aminogroup, water-soluble acidsalts can be prepared and the azo compounds are accordinglyparticularly useful'in aqueous polymerization systems.

" The azo compounds of this invention are readily obtained by the reaction of a ketone containing a tertiary aminegroup with hydrazine followed by reaction with hydrogen cyanide. The resulant hydrazo compound can be oxidized with chlorine or bromine to the desired amino azonitrile. The cyano group can be. converted into various derivatives'r. g} esters oramides' through.

the im'ide hydrochlorit ie.-

The following exam es in which a. as

given arev by" weight further illustrate the min ciples involved in this invention. The first. examples (I, II, and III) show representative 'azomaltsm? he s bs q ai x l s ate the use of these compounds in the polymerization of ethylenically unsaturatedcompounds.

. EXAMPLE I Alphmalpha' -azobis (-alp'lm methyl gamma-diethyhominobutyronitriie) A total of 42.5 parts of diethylamine hydrochloride, 32 parts of 37% forma1dehyde and 90.5 parts of acetone was refiuxe'djfor twohours with the distillation of 24 partsjof acetone from the re-. action mixture, followed by heating the mixture (to which six parts of paraformaldehyde had been added) in a closed vessel for three hours at 100 C. Ether was then added and the aqueous layer made basic with sodium hydroxide. The oil was extracted with ether and gave upon distillation 25 parts of methyl beta-diethylaminoethyl.ketone. This ketone was reacted .with founpartsoi hydrazine hydrate at 25-50" c; ruffle-hours and after cooling in an ice bath adjusted to a pH of about 6 (by adding 6.2 parts of hydrogen chloride in 20 parts of aqueous solution). This solution was mixed with 42parts of hydrogen cyanide. After standing for-about 16 hoursat room temperature, excess hydrogen cyanide was removed by evaporation, 100 parts or water added and the solution cooled to 5-10 C. Chlorine-'waspassed into the solution until free halogen' was present. A portion of this solution was employed as a catalyst for the polymerization'of'acrylonitrile in water solution. The remainder was neutralized with an excess of sodium hydroxide solution (about-=20 parts of 21.40% solution) and the o'ilextracted by ether. Evaporation of the ether-gave 17 parts of liquid azonitrile (64% yieId-basedon- Anal sis-Neutral equivalent: escalat 167.

AZphanZ'p-ha aaoliistdlpha-methyl deltq- Y diethyl-aminovolero nitrile) v A mixture of 49 parts of diethylamine, boiling at 555 C. was refluxed with 40 parts of methyl gamma-chloropropylketone for 48 hours with stirring. A solution of 20 partsof .sodiumhydroxide in parts 'oiwaterlwasadded-and the diethylamino2-pentanone. This amino ketone was charged in a flask with 4.7 parts of hydrazine hydrate and the mixture allowed to react at room temperature with stirring for 24 hours. To this solution was added a mixture of about 20 parts of concentrated hydrochloric acid and 15 parts of water to "give a'solution having a'pI-I of 6. To this solution was added 28 parts of hydrogen cyanide. After standing 24 hours, excess hydrogen cyanide was removed by evaporation; 100

parts of water added, cooled to5 C. and chlorine passed into the solution until free halogen was present. The reaction mixture was made basic with a 40% sodium hydroxide solution and the oil which separated was extracted'with ether,

dried and the solvent removed iun'der' reduced pressure. The azo compound (26 parts) V8501?! tained as a clear yellow oil corresponding to a he-formu a 'ani zzysi x-icalc'ui ata"rel cararmancn N. 18.3,0%;f(1 l, 15.45%; Found: N, 17.36%; Cl, 15.63%.j'Thejhydifdchloride melted with decom- A stainless .steel-line d high-pressure reaction vessel was charged withlOO parts of water and 0.2 Part oithe .a r e of E mp I a h alpha'rr azcbisia p a m y a a e y aminobutyronitrilen'. The reactor was closed, flushed; with nitrogen, 1 evacuated and pressured with ethylene. The temperature was raised to 7 0 C;-.;jor aperiod of 11 hours with ethylene maintained at a pressure of about 900 atmospheres. A yield of 6 parts of solid ethylene polymerwas obtained The polymer had an intrinsic viscosity of -1.0 8, a tensile strength of 2650 lb./sq.in. at 5.60 elongation and amelting point of 122 C. H EXAMPLE V The general polymerization procedure of Example IV was repeated except that 80 parts of benzene was used as the inert diluent in place of water and 0.1 part of the 'azonitrile of Example II (alpha,alpha azobis (alpha methyl oin'eg'adiethylaminovaleronitrile)) was employed as the catalyst. The polymerization temperature was 100 C. for 8 10hours There was obtained 6.5 parts of solid ethylene polymer which had an intrinsic viscosity of 0.86.

EXAMPLEVI A reactor was charged with 78 parts of cyclohexane, 21.2 parts of acrylonitrile, and a polymerization catalyst and heated; When the yieldf qf the'corre'sponding-piperidino azonitrile of catalyst'was 0,19 part of the product of Example I (alpha,'alpha" az'obislalpha methyl gammaremoved from e. g. methyl, ethyl,- or but 1 -yield-of polyacrylonitrile was obtained.

EXAMPLE v11 A totalof ldOvpa-rt's of vinyl acetate was dissolved 'in abdut '80 parts of tertiary-butyl alcohol "and 0.5 part oitalpha, alpha azobis(alphamethyl gamma diethylaminobutyronitrile) added. After agitation at C. for 10 hours, a 21% yield of polyvinyl acetate was obtained.

EX PLE v Partof the menswear-nae; elnhee ha'+ i p ai e hy gamma -s etb 3. .1 butyronitrilelx After l-ljllOllIS at.6 0

as o n d ..f,1 %.-;r e1.d. .0? l y ny b ofi iem N=Nr.. .u tle tpra tiseva a e of w i i bond t rtiar arbo 0 a s id, r ca 11101101731163? nq f a f 51 containing a. er ia y mi e we. rid/rew ing on said tertiary carlqon acarbon ll of whose mai i 'va e c s e eb id lltd wa l'q nitrogen, f r l the am ro p... i bende o two u adl e fie Th ses iuemon d to e t i arp amarb 91. e mp e a wer group, a carbonamido. group. or a lower carbalkoxy COOR group wherein R is mealt me ex e q 91 pm iwa ppnsi "Pr rab the az o compound cohtainsgonly hydrogen saturated aliphaticcarbon andjh" cyandltertiaryp a .7 iber e n ou may be atta he tqemt erh i *Whibfiisthe .group-hyatlast one amino and azo nitrogen.

carbon.

The'invention pha' azobis (alpha-inethyl beta dim'tliylammo propionit'rile) and alpha,aliihaf-azokiisialphamet ticgn to those of the exariibls" me are Je e ..e'nd midssaiealikv elu e in this invention. Theesters and arm desv are I the "am nitrogerisl; The rer rree1.campetaas; may he represented by tneprbimma" I 1?; J .1

mazmcnz) tome-(mime,

' NcwNlmelemgtaat and Ra are lower hydro methyl to b'utyl'and'zc nd pr a y. w3 v l ese (=0 7 45 c r-its r ared t lowing 'ste'ps'z" fa) treatment of the isfthfeibiiiehdidalph 31.;

The correspondor ation;

mesa ee ie ainmo'nia amine-containing ketone with hydrazine to form the azine, (1)) treatment of the resultant azine with hydrogen cyanide to form the corresponding hydrazonitrile, and oxidation of the hydra-zonitrile with chlorine or bromine to give the azonitrile. The above steps are preferably carried out in aqueous medium with the ketone present as a salt of the amino group. Steps (a) and (b) are preferably carried out at moderate temperatures such as 2575 C. while the oxidation step (c) is generally at lower temperatures, e. g. to C. The azonitrile can be obtained by addition of alkali to the salt although as shown in Example I and for many similar polymerizations in aqueous systems the water-soluble salts may be used directly.

An important advantage exhibited by the azonitriles of this invention is their ability to be used as salts in water systems for polymerization reactions, particularly in acidic aqueous systems.

The azo compounds and particularly the azonitriles of this invention are of utility as catalysts for chain reactions, e. g. chlorination and chlorosulfonation, and particularly polymerization catalysts in the addition polymerization, including copolymerization, of polymerizable compounds containing ethylenic double bonds. The invention is generic to the polymerization of ethylenic compounds subject to polymerization, including monoolefins, e. g. ethylene, isobutylene and styrene; diolefins, particularly butadiene; vinyl esters, e. g. vinyl chloride, vinyl fluoride, vinyl acetate, vinyl propionate; vinylidene halides, e. g., vinylidene chloride and fluoride; vinyl ethers and ketones, e. g. vinyl butyl ether and methyl vinyl ketone; acrylyl and methacrylyl compounds, e. g. acrylonitrile, methyl methacrylate; polyfluoroolefins, e. g. tetrafluoroethylene, trifluorochloroethylene, and 1,1-di fiuoro-2,2dichloroethylene; and compounds containing two or more isolated or conjugated double bonds, e. g. the diacrylic acid esters of glycols and polyethylene glycols, for example, tetraethylene glycol dimethacrylate, diallyl diglycolate, diallyl carbonate, diallyl phthalate, chloroprene, and fluoroprene. A particularly important group to which the majority of the above polymerizable compounds belong is that of polymerizable compounds having a CH2=C group, i. e., a terminal methylene group, i. e., a terminal ethylenic linkage.

The amount of the azo compound to be employed varies between 0.001 and 5%. The temperature usually employed is 40-125 C. or higher. Lower temperatures can be used when light is employed in conjunction with the azo compound. The polymerization can be carried out in bulk, solution, granulation, or emulsion systems.

In addition to the use of the azo compounds of this invention as polymerization catalysts, decomposition of the azo compounds by heating until nitrogen is evolved produces the corresponding dibasic acid derivatives in which the carboxylic derivative groups, e. g. the nitriles, are attached to adjacent carbons. Such derivatives may be used as intermediates in organic reactions.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described for obvious modifications will occur to those skilled in the art.

What is claimed is:

1. An aliphatic azo compound in which the azo group is acyclic and has each of its valences bonded to tertiary carbon of a monovalent aliphatic radical of 6 to 11 carbon atoms, said tertiary carbon being bonded to (a) a cyano, CN, group, (b) an alkyl radical, and (c) a dialkylaminoalkyl radical.

2. An azo compound in which the azo group is acyclic and has each of its valences bonded to tertiary carbon of a monovalent radical of 6 to 11 carbon atoms, said tertiary carbon being bonded to (a) a cyano, CN, group, (b) an alkyl radical, and (c) an alkyl radical having a tertiary amino nitrogen on carbon at least one carbon removed from the free valence, the tertiary amino nitrogen having its remaining valences bonded to members of the class consisting of alkyl radicals and radicals which together with the tertiary nitrogen form a heterocyclic ring.

3. An azo compound in which the azo group is acyclic and has each of its valences bonded to tertiary carbon of a monovalent radical of 6 to 11 carbon atoms, said tertiary carbon being bonded to (a) a cyano, CN, group-(b) an alkyl radical, and. (c) an alkyl radical having; on carbon at least one carbon removed from the free valence a tertiary amino nitrogen the remaining valences of which are bonded to a divalent radical forming with the nitrogen a heterocyclic ring.

4. Alpha,alphaazobis(alpha methyl deltadiethylaminovaleronitrile) 5. Alpha,alpha azobis(alpha methyl deltapiperidinovaleronitrile) 6. Alpha,alpha'-azobis(alpha-methyl gammadiethylaminobutyronitrile) JOHN RAVEN JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,471,959 Hunt May 21, 1949 2,492,763 Pinkney Dec. 27, 1949 2,515,628 Castle July 18, 1950 2,520,338 Robertson Aug. 29, 1950 

5. ALPHA, ALPHA'' -AZOBIS(ALPHA - METHYL - DELTAPIPERIDINOVALERONITRILE). 